46 CELLULAR STRUCTURE OF THE RED BLOOD-CORPUSCLES. 
himself the body of the corpuscle as composed of a living 
organism, whose central portion forms the nucleus of all 
nucleated red blood-globules, and is free from haemato-glo- 
bulin, while the remaining portion contains the entire mass 
of the latter. The last-mentioned part Briicke considers as 
lying in the interspaces of the porous mass, filling them 
completely, but at the same time forming a continuous whole 
with the non-pigmented portion. The colourless porous 
substance he calls Oikoid, all the remainder he names Zooid; 
and considers that, by the partial or complete withdrawal of 
the Zooid from the Oikoid, the occurrence of the above- 
mentioned appearances is explained. Strieker himself be¬ 
lieves in the Oikoid of Briicke, but calls the remainder of 
the corpuscle its body (der Lieb)/ ; 
Recapitulating now the facts which I have detailed, mili¬ 
tating against the views of Flint, Beale, and Ch. Robin, who 
hold that the red blood-corpuscles of mammals are homo¬ 
geneous drops of a jelly-like substance, we find, first, that 
when human blood is diluted with pure water the bi-concave 
disks in general gradually assume a bi-convex and finally a 
globular form, their coloured portion being entirely dissolved, 
sometimes in the course of a few minutes, while the trans¬ 
parent colourless constituent which retains the spherical shape 
is completely insoluble in water, even during the prolonged 
maceration of over thirty days; and second, that when a 
mass of desiccated corpuscles, such as occurs in a dried 
blood-clot, is washed with pure water, so as to remove all the 
haemato-crystallin, the outlines of the compressed red blood 
disks may be readily detected on examination with a suffi¬ 
ciently high power; further, that in the red globules of the 
Menobranchus, which may be supposed to bear a more or 
less close analogy in their constitution to those of mammals, 
it is possible to analyse the corpuscle by separating the co¬ 
loured cell contents from the colourless cell wall, either by 
puncture of the membrane, by crystallization of its enclosed 
fluid, or by pressure upon the corpuscle, forcing out its con¬ 
tents apparently through the pores of the membranous cap¬ 
sule in the same manner that quicksilver is strained by 
pressure through the sides of a buckskin bag. 
In opposition to the theories of Hensen, Strieker, and 
Briicke, who consider the red blood-corpuscles are made up 
of a colourless porous substance called Oikoid, and a coloured 
more fluid ingredient denominated Zooid, may be enumerated 
the following circumstances:—First, if, on the one hand, we 
consider that a porous substance of the definite bi-concave 
form, analogous to a disk of compressed sponge, exists, it 
